Circuit breakers are commonly mounted within an electrical enclosure or draw out unit to provide overcurrent protection to a circuit. A line side of the circuit breaker is connected to an electrical power line supplying electricity and a load side of the circuit breaker is connected to the circuit to be protected. In all circuit breakers, the separation of the breaker contacts due to a short circuit causes an electrical arc to form between the separating contacts. The arc causes the formation of relatively high-pressure gases as well as ionization of air molecules within the circuit breaker. These high-pressure gases can cause damage to the breaker casing. The gases, therefore, must be vented from the circuit breaker enclosure. In addition, a phase-to-phase fault can occur if the arc gases from different phases are allowed to mix, and a phase-to-ground fault can occur if the gases contact the grounded enclosure. To avoid a phase-to-phase or phase-to-ground fault, gases vented from different phases must be kept separate from each other and away from the grounded enclosure until the ionization has dissipated. These high temperature gases must exit the circuit breaker enclosure in order to prevent the circuit breaker enclosure from becoming over-stressed. Ventilated circuit breakers provide openings within the circuit breaker enclosure to allow the ionized gases to exit the circuit breaker in a controlled manner.
U.S. Pat. No. 5,241,289, entitled xe2x80x9cExhaust Arc Gas Manifoldxe2x80x9d describes one means for controlling the egress of gases from a three phase circuit breaker enclosure. The arc gases exiting through the ventilation slot of one line terminal compartment must be prevented from contacting a line terminal connector within an adjacent line terminal compartment to prevent a so-called xe2x80x9cphase-to-phasexe2x80x9d fault. The approach disclosed in U.S. Pat. No. 5,241,289 to prevent the occurrence of short circuits between the line end conductors of different phases utilizes a manifold disposed at the line end conductors. The manifold channels the center phase exhaust arc gas directly outward and channels the phases on either side of the center phase generally perpendicular to the center exhaust arc gas direction and in opposite directions to each other. This practice works well when space is abundant surrounding the circuit breaker to allow egress of the exhaust arc gas from the circuit breaker.
However, modern circuit breaker designs are becoming more compact and are required to handle additional power in smaller enclosures than conventional circuit breakers. Due to the reduction of internal space and higher current levels, the gases produced when opening the circuit in question are more intense and at higher temperatures. Furthermore, as space surrounding the circuit breaker is reduced, the likelihood of phase-to-phase and phase-to-ground arcing is increased. Thus, an apparatus is needed to provide protection from short circuits for interruption circuit breakers during the interrupt condition utilized in smaller electrical enclosures to divert exhaust arc gases in a manner that does not cause phase-to-phase and phase-to-ground arcing. Furthermore, an apparatus that provides protection that can be field installed as an add-on feature to any type of circuit breaker is needed.
The above discussed and other drawbacks and deficiencies are overcome or alleviated by an exhaust arc gas manifold attachable to a circuit breaker, the manifold comprising: an electrically-insulated body having an upper wall and a lower wall joined by a back wall extending generally perpendicular to the upper and lower walls; a pair of electrically-insulated walls extending generally perpendicular from the back wall between the upper and lower walls defining a first section, a second section, and a third section; the first section is closed at a bottom, back and both sides thereof; the second section is closed at a top, bottom and both sides thereof; the third section closed at a bottom, back and both sides thereof; and the upper wall configured to attach the electrically-insulated body to one end of the circuit breaker, wherein exhaust arc gas is emitted from a top of the first and third sections and from a back of said second section.